Performance and the Right

Editorial for Special Issue An introduction to the Special Issue, this editorial highlights the changes (or otherwise) in the global socio-political landscape since the Special Issue was first proposed in late 2018. It offers a brief introduction to each article, a rationale for the structure of this issue, and advocates for the importance of scholarship that examines the relationship between performance and right-wing politics

Análise do desempenho de um sistema de aeração por difusor poroso de bolha fina instalado no reator biológico aeróbio (RBA) da estação de tratamento de dejetos suínos (ETDS) da Embrapa.

Projeto/Plano de Ação: 02.07.60700-04

Uso de lodo ativado com sistema de aeração por difusor poroso de bolha fina para o tratamento de dejetos da suinocultura.

Projeto: 02.07.06.007

Identification of ancient gilding technology and Late Bronze Age metallurgy by EDXRF, Micro-EDXRF, SEM-EDS and metallographic techniques

A combination of analytical techniques capable of elemental and microstructural characterisation was used for the identification of ancient gilding technology and bronze metallurgy. EDXRF, micro-EDXRF, SEM-EDS analysis and metallographic examinations were applied in the study of artefacts dating to the end of the second millennium BC from Crasto de São Romão in Central Portugal. Results report to the finding of an exceptional gilded copper nail among bronze artefacts with 9 wt.% to15 wt.% tin and minute other metallic impurities. Additionally, analysis of a crucible fragment points out for bronze production at the archaeological site. EDXRF and micro-EDXRF analysis made on the copper nail showed that it was gilded only on the front side of the head, and that the gold layer has been lost in the most exposed areas. SEM-EDS analysis showed that the gold layer has 5–8 μm in thickness and is covered with a thick corrosion layer. The gilding technique is discussed based on the gold layer composition and gold/copper substrate interface. So far, this object seems to be the first diffusion gilded artefact identified in the Portuguese territory dated to Late Bronze Age

Energy relaxation of an excited electron gas in quantum wires: many-body electron LO-phonon coupling

We theoretically study energy relaxation via LO-phonon emission in an excited one-dimensional electron gas confined in a GaAs quantum wire structure. We find that the inclusion of phonon renormalization effects in the theory extends the LO-phonon dominated loss regime down to substantially lower temperatures. We show that a simple plasmon-pole approximation works well for this problem, and discuss implications of our results for low temperature electron heating experiments in quantum wires.Comment: 10 pages, RevTex, 4 figures included. Also available at http://www-cmg.physics.umd.edu/~lzheng

Smelting and recycling evidences from the Late Bronze Age habitat site of Baiões (Viseu, Portugal)

Many aspects of bronze production during Late Bronze Age in Western Europe are so far unknown. In the present study selected artefact fragments and metallurgical debris, which include a slag fragment, from the emblematic Late Bronze Age habitat site of Castro da Senhora da Guia de Baio˜es (Viseu, Portugal) have been studied by optical microscopy, micro-EDXRF, SEM–EDS and XRD. Evidences were found for bronze production involving smelting and recycling. Compositional analysis showed that the artefacts are made of a bronze with 133 wt.% Sn (average and one standard deviation) and a low impurity pattern, namely <0.1 wt.% Pb, being comparable with the composition of other bronzes from the same region (the Central Portuguese Beiras). This alloy is generally different from elsewhere Atlantic and Mediterranean bronzes, which show frequently slightly lower Sn contents and higher impurity patterns,namely Pb which is often present as an alloying element. The present study gives further support to early proposals suggesting the exploration of the Western Iberian tin resources during Late Bronze Age, and besides that, it indicates that metalworking and smelting could have been a commonplace activity requiring no specific facilities, being bronze produced at a domestic scale in this Western extreme of Europe

Estrutura e Dinâmica de taxocenoses de Diptera: Simuliidae em sistemas lóticos preservados e impactados no Parque Nacional do Itatiaia, RJ

Os simulídeos são insetos popularmente conhecidos como borrachudos, cujas larvas desenvolvem-se em águas correntes e encachoeiradas, e nutrirem-se de detritos orgânicos. Estes insetos estão amplamente distribuídos ao redor do globo, sendo encontrados em todos os continentes. A família Simuliidae (Diptera) compreende algumas espécies vetoras da Oncocercose e da Mansonelose, além de existirem relatos na literatura apontando sua relação com o Pênfigo Foliáceo endêmico. São extremamente importantes como indicadores da qualidade da água, já que podemos relacionar a população dos simulídeos com a quantidade de matéria orgânica nos rios, de modo que aumentos no tamanho populacional destes insetos podem indicar aporte de dejetos domésticos, agrícolas e industriais no local analisado. Desta forma, busca-se avaliar a influência dos níveis de poluentes na água sobre a estrutura e composição das comunidades de simulídeos em rios dentro da área de proteção do Parque Nacional do Itatiaia e fora da mesma, em ambiente urbano. Serão realizadas coletas sazonais, nas quais amostras da água serão coletadas juntamente com o material biológico e encaminhadas para análise em laboratório do UNIFOA

A sustainable reaction process for phase pure LiFeSi2O6 with goethite as an iron source

Lithium-iron methasilicate (LiFeSi$_{2}$O$_{6}$, LFS), a member of clinopyroxene family, is an attractive compound for its multiferroic properties and applicability in energy-related devices. Conventional preparative method requires heating at elevated temperatures for long periods of time, with inevitable severe grain growth. We demonstrate that α-FeO(OH) (goethite) is superior as an iron source toward phase pure LFS over conventional hematite, α-Fe$_{2}$O$_{3}$. The exact phase purity, i.e., no trace of iron containing reactant, is confirmed in the goethite-derived LFS by 57Fe Mössbauer spectroscopy. The grain growth of LFS during heating is suppressed to keep its crystallite size of 120 nm. Higher reactivity of goethite in comparison with hematite is mainly attributed to the dehydration of goethite, which in our case was accelerated by Li$_{2}$O. Related reaction mechanisms with the possible product pre-nucleation during mechanical activation are also mentioned. The magnetic properties of goethite-derived LFS are equivalent to those prepared via a laborious solid-state route. Thus, the presented preparative method offers a more sustainable route than conventional processing, and thus enables practical application of LFS